Hydraulic piston soil sampler



Feb. 28, 1967 w. E. WOODS L HYDRAULIC PISTON SOIL SAMPLER Filed March 20, 1964 Fics. 4:

INVENTOR. WLB QT E. WOODS ATTOQNEy United States Patent Oiice 3,3%,l l@ Patented Feb. 28, i967 3,396,11@ HYDRAULIC PISIN SQIL SAMPLER Wilbert E. Woods, Harvey, Ill., assignor to the United States of America as represented by the Secretary of the Army Filed brian 2t?, Hdl-l, Ser. No. 353563 Ciams. (Cl. i3-421) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates generally to soil samplers and in particular to an improved soil sampler actuated by a double acting -piston and cylinder.

Present technologyin the field of location and exploitation of underground resources relies extensively on geological interpretation of the composition of subsurface strata. In obtaining samples of these strata it is necessary that the sample be presented for examination substantially undisturbed from its condition within the earth. This is particularly ditiicult when dealing with samples of tine grained soils such as high plasticity clays, silt soils and highly organic soils. With the soil samplers available to the art there is a tendency to overpush the samples thereby consolidating and disturbing th-e orientation `of the sample. Once the sample has been -obtained it is also necessary to remove the sample from the sampler without disturbing the sample itself. The device of this invention develops the thrust necessary to obtain the sample at the sampler rather than at the drill thereby preventing overpushing and also provides positive means Ifor removing the sample from the sampler in an undisturbed manner.

It is accordingly a primary object of this invention to provide a soil sampler capable of obtaining undisturbed samples of subsurface strata.

It is another object of this inventi-on to provide a soil sampler wherein the sampling thrust is developed at the sampler rather than at the drill assembly.

It is another object of this invention to provide a sampler wherein the sample is both taken into and ejected from the sampler by a torce exerted by a double acting piston.

These and other objects and advantages of theinventio-n will be readily apparent from the following description of the invention with reference to the accompanying drawings wherein:

FIG. 1 is a view or" the soil sampler of the instant invention inserted in a bore hole just prior to sampling;

FIG. 2 is a view of the soil sampler as in FIG. 1 in its extended sampling position;

FIG. 3 is an enlarged sectional view of the soil sampler in the position of FIG. l; and

FIG. 4 is an enlarged sectional view of the sampler in the position of FIG. 2.

As shown by FIGS. 1 and 2 the soil sampler of this invention (represented generally by the numeral l) consists of a hydraulic cylinder 2 having lower end cap 3 and upper end cap 4 Imounted securely on opposite ends thereof. Lower end cap 3 carries soil sample tube 5 mounted thereon.

Hollow piston rod 6 passes through an axial hole in upper end cap 4, said hole being overbored for a portion of its length to accommodate packing 7 and being provided with threads along the upper portion thereof for engagement with packing nut 8 through which the piston rod 6 also passes. The upper end of hollow piston rod 6 is sealed by means of plug 9. Hydraulic piston l@ and rubber piston cup means 11 are held in place on the lower end of hollow piston rod 6 by means of upper and lower piston retaining nuts 12 and 13, respectively.

Upper retaining nut i?. is threadably engaged with external threads on the hollow piston rod 6. Sample tube piston rod le passes through an axial hole in lower end cap 3, said hole being overbored in two stages to accommcdate pecl-:ing 15 and packing retainer lo which is held f" to the lower face of end cap 3 by means of circum- .ially disposed screws t7. The upper portion of sample tube niston rod i4 is provided with external threads which engage internal threads on the lower portion of hollow pist-on rod 6. Lower retaining nut 13 is threadably engaged with these threads in such a manner that the hydraulic piston 1l) and piston cups Il are firmly held in place between retaining nuts I2 and I3. An axial bore 18 is provided in the upper end of sample tube piston rod 6 said bore 1S communicating with radial ports 19 in lower retaining nut 13 forming a fluid conducting passage between the interior of hollow piston rod and the enclosed Volume below hydraulic piston l0. A port Zd supplied with a fitting 21 is provided in the portion of the hollow piston rod 6 external to the cylinder 2 to permit the introduction of hydraulic fluid into the volume enclosed below the hydraulic piston 10. Likewise a port 22 `supplied with .fitting 23 is provided in upper end cap 4 to permit the introduction of hydraulic fluid into the volume enclosed above hydraulic piston 19.

The lower end of sample tube piston rod 14 has soil piston 24 mounted firmly thereon. This may be accomplished, for example, by means of tapered bushing 25 threadably engaged with the soil piston rod 14. A tapered hole is provided in soil piston 24 to receive the tapered bushing 25 and a washer 26 and nut 27 threadably engaged with the upper end of the bushing rmly hold the soil piston 24 in place. The soil sample tube 5 is approximately the same length as the hydraulic cylinder 2 and the soil piston rod is of sucient length to bring the lower end of the soil piston 24 to a position just within the lower, open end of soil sample tube 5 when the hydraulic piston lll is at the lower end of its travel. In addition a vent 28 is provided in lower end cap 3 to permit the escape of the air above soil piston 24 when said piston travels upwardly into the soil sample tube 5.

In operation the soil sampler 1 is connected to a drill rod 29 by `means of coupling 3l) threadably engaged to the ends of hollow piston rod 6 and drill rod 29. The drill rod is connected to a conventional drilling rig (not shown) on the surface of the earth. The soil sampler 1 is lowered into the bore hole 31 to be sampled with the hydraulic piston il@ in its lowest position as shown in FIGS. 1 and 4. After the soil sampler 1 reaches the bottom of the bore hole 31 hydraulic fluid under pressure is introduced from the hydraulic system of the drilling rig (not shown) into the volume enclosed below the hydraulic piston l!) by means of uid line 32 communicating with the interior of hollow piston rod 6. Since hydraulic piston 10 is xediy connected to hollow piston rod 6 which is in turn connected to drill rod 29, the entire weight of the drilling rig acts to resist upward movement of the hydraulic piston lil. The hydraulic pressure therefore acts on the inner face of lower end cap 3. This force causes lower end cap 3 to move downwardly `forcing the s-oil sample tube 5 into the strata to be sampled, withdrawing soil piston 24 into the soil sample tube 5 and causing hydraulic cylinder 2 and upper end cap 4 t-o slide downwardly along hollow piston rod y6 until the condition shown in FIGS. 2 and 3 is reached. As soil sample tube 5 is forced into the earth a partial vacuum is created between the sample 33 and the lower face of soil piston 24 and said vacuum aids in keeping the sample 33 in the sample tube 5 during removal of the sampler 1 from the bore hole.

The soil sampler 1 containing soil sample 33 is then lifted from the bore hole and brought to the surface. Hy-

is then supplied to the volume above hydraulic piston 10 by means of line 34. This causes hydraulic piston 10 to move back to the position shown in FlG. 3 thereby causing soil piston 24 to force the soil sample 33 from sample tube 5. To facilitate recovery of the sample a tubular waxed cardboard container may -be mounted on the open end of sample tube 5 and the sample 33 forced di-rectly thereinto.

In actual practice soil samples 30 inches long and 5 inches in diameter have been obtained in fine grained Soils such as highly plastic clays, silt soils and highly organic soils. The recovery rate of undisturbed samples has been consistently about 96%. With a 5 inch LD. sample tube a partial vacuum of 10.3 p.s.i. is created between the soil sample 33 and the soil piston 24. When the hydraulic cylinder has an inside diameter of 4 inches and the soil piston rod has a diameter of 1 inch the sampler can develop a thrust of 9800 pounds when 1000 p.s.i. hydraulic uid is used. It is obvious that the drilling equipment such as the drilling rig, rods and machine itself must weigh more than 9800 pounds in order to prevent the hydraulic piston from moving up when pressure is applied during the sampling phase.

It is also obvious that pneumatic pressure could be used instead of hydraulic pressure to operate the soil sampler of the instant invention. For all intents and purposes the terms hydraulic and pneumatic may be considered as equivalent with respect to the functioning of this invention.

The preceding description relates merely to a preferred embodiment of the instant invention and the invention should not be construed as being limited to the specic details of construction shown therein. The scope of the invention is set forth in the following claims.

I claim:

1. A soil sampler comprising:

(a) a hydraulic cylinder;

(b) a hydraulic piston within said cylinder;

(c) upper and lower connecting means extending from opposite ends of said hydraulic piston, said connecting means passing through fluid sealed passages provided in upper and lower ends, respectively, of said hydraulic cylinder;

(d) means for supplying hydraulic fluid under pressure to the volumes enclosed above and below said hydraulic piston;

(e) sampling means depending from the lower end of said hydraulic cylinder and;

(f) a piston within said sampling means connected to the lower end of said lower connecting means; the relationship between the lengths -of the sampling means, piston stroke, and upper and lower connecting `means being such that the piston is at a position just within the lower end of said sampling means draulic pressure when the hydraulic piston is at the lower end of its stroke and said sampling means is of sufficient length to permit withdrawals of said piston within said sampling means when said hydraulic piston is at the upper end of its stroke, and said upper connecting means being of sutcient length so that a -portion thereof extends beyond the upper end of said hydraulic cylinder when the hydraulic piston is at the lower end of its stroke.

2. The apparatus of claim 1 wherein vent means are provided in the volume enclosed above said piston.

3. The apparatus of claim 1 wherein the upper end of said upper connecting means is provided with coupling `means for connection to a drill rod.

4. The apparatus of claim 1 wherein said means for supplying hydraulic fluid under pressure t-o the volume enclosed below said hydraulic piston comprises a passageway within said upper connecting rod communicating at its lower end, with the volume below the hydraulic piston and being posted Vthrough the upper connecting means at a point on said connecting means that is exterior to said hydraulic cylinder when the hydraulic piston is at the lower end of its stroke.

5. A soil sampler comprising:

(a) a hydraulic piston and cylinder actuator, the piston of which is maintained in a relatively fixed position, and the cylinder of which is movable with respect to the piston, said cylinder including an inlet for supplying hydraulic fluid to the upper portion thereof;

(b) a hydraulic piston within said cylinder, said piston having means for passing hydraulic fluid through said piston thereby creating pressure in the lower portion of said cylinder; and

(c) sampling means attached to said cylinder and actuated by the hydraulic fluid pressure against lower portion of said cylinder thereby forcing said sampling means in a downward direction to place said sampling means in sample receiving condition, said sampling means actuated by supplying hydraulic uid through said inlet in said cylinder to the top surface of said piston thereby forcing said sampling means in sample ejecting condition.

Engineering News-Record, July 20, 1939, pages 58-60. volume 123 (volume page numbers 82-84).

LOUIS R. PRNCE, Primary Examiner.

S. C. SWISHER, Assistant Examiner. 

5. A SOIL SAMPLER COMPRISING: (A) A HYDRAULIC PISTON AND CYLINDER ACTUATOR, THE PISTON OF WHICH IS MAINTAINED IN A RELATIVELY FIXED POSITION, AND THE CYLINDER OF WHICH IS MOVABLE WITH RESPECT TO THE PISTON, SAID CYLINDER INCLUDING AN INLET FOR SUPPLYING HYDRAULIC FLUID TO THE UPPER PORTION THEREOF; (B) A HYDRAULIC PISTON WITHIN SAID CYLINDER, SAID PISTON HAVING MEANS FOR PASSING HYDRAULIC FLUID THROUGH SAID PISTON THEREBY CREATING PRESSURE IN THE LOWER PORTION OF SAID CYLINDER; AND (C) SAMPLING MEANS ATTACHED TO SAID CYLINDER AND ACTUATED BY THE HYDRAULIC FLUID PRESSURE AGAINST LOWER PORTION OF SAID CYLINDER THEREBY FORCING SAID SAMPLING MEANS IN A DOWNWARD DIRECTION TO PLACE SAID SAMPLING MEANS IN SAMPLE RECEIVING CONDITION, SAID SAMPLING MEANS ACTUATED BY SUPPLYING HYDRAULIC FLUID THROUGH SAID INLET IN SAID CYLINDER TO THE TOP SURFACE OF SAID PISTON THEREBY FORCING SAID SAMPLING MEANS IN SAMPLE EJECTING CONDITION. 